Underwater pool lights are used in swimming pools, wading pools, fountains and spas for illumination under the surface of the water. Underwater pool lights generally require a niche in a wall of the pool for installation of the light. This requires extra excavation and concrete reinforcing or extra gunite to install the light in a gunite pool. As a result, most underwater lights are bulky and expensive to install. In vinyl liner pools, additional reinforcing is usually required, and large holes, nine to twelve inches wide, are needed to install wet niche lights. This type of installation also increases the chance of leaks in vinyl liner pools. Many conventional lights cannot be used in vinyl liner pools.
Some underwater lights must be removed and completely disassembled to replace a bulb, adding to their inconvenience and requiring experienced personnel for maintenance. Other underwater lights have no heat sensing device to prevent overheating. Besides presenting a safety hazard, overheating reduces bulb life and increases maintenance costs.
Some underwater lights use clear covers or lenses and provide no directional control over the light output. These lights have a tendency to illuminate not just the pool but also the surrounding area. The resulting glare is both an inconvenience and a safety hazard. Fountain lights also should be appropriately directed to avoid unwanted glare. Underwater lights should include an effective reflector to direct light out into the pool.